At end of combat, if Clockwork Beast attacked or blocked this combat, remove a +1/+0 counter from it.

, : Put up to X +1/+0 counters on Clockwork Beast. This ability can't cause the total number of +1/+0 counters on Clockwork Beast to be greater than seven. Activate this ability only during your upkeep.

Loses a counter even if it is affected by a Fog-like effect which prevents it from dealing damage.

10/4/2004

Can attack or block even if it has no counters.

9/16/2007

This is a change from the most recent wording. Now, if some other spell or ability causes +1/+0 counters to be put on Clockwork Beast, it can wind up with more than seven such counters on it.

9/16/2007

If Clockwork Beast has seven or fewer +1/+0 counters on it when its last ability resolves, it can wind up a maximum of seven such counters on it. If it has seven or more +1/+0 counters on it, the ability will have no effect.

9/16/2007

Clockwork Beast’s last ability resolves, you can choose to put fewer than X +1/+0 counters on it.